Sleep disorders: Profound effects on pediatric health

Polysomnography is performed at the Center for Sleep Medicine at Mayo Clinic in Rochester, Minn.

Although public awareness of the link between sleep and health in adults has grown substantially, the impact of sleep disorders on child health and development has only recently gained recognition. In 2000, Mayo Clinic conducted approximately 20 pediatric sleep studies. Today, Mayo performs more than 800 annually.

Suresh Kotagal, M.D., a pediatric neurologist and sleep medicine specialist at Mayo Clinic in Rochester, Minn., notes that sleep disturbances may affect as many as 30 percent of children. These disturbances not only can impact the developing brain; they also can profoundly affect quality of life for children and their families. Having trained in the 1980s with a pioneer in the field of sleep medicine, William C. Dement, M.D., Ph.D., Dr. Kotagal has devoted his career to managing pediatric sleep disorders and training others to do so. He is co-author of the first textbook on sleep disorders associated with pediatric neurologic conditions.

As in adults, primary sleep disorders in children can be respiratory or neurologic in origin. They can include obstructive sleep apnea, restless legs syndrome (RLS) and narcolepsy. The symptoms, however, may differ in children. For example, children who are sleep deprived may be hyperactive and inattentive during the day rather than somnolent. As a result, these children may be misdiagnosed and treated for attention deficits when their primary problem is sleep impairment.

The diagnostic criteria, as defined by the American Academy of Sleep Medicine in 2007, also differ for children in tests such as the multiple sleep latency test and nocturnal polysomnography. Treatment strategies may differ as well. For example, the first step in management of childhood obstructive sleep apnea is often adenotonsillectomy, rather than placement on a positive airway pressure device. And, while RLS after age 40 years may be a sign of degenerative neurologic disease, in children genetic predisposition and iron deficiency are key factors, as Dr. Kotagal and Michael H. Silber, M.B., Ch.B., co-director of Mayo Clinic's Center for Sleep Medicine, found in a 2004 study. Their findings were published in the December 2004 issue of Annals of Neurology. Rather than the drug therapies applicable to adults, the best treatment in children may be replenishing iron stores and improving iron absorption.

Mayo's three pediatric sleep medicine specialists — Dr. Kotagal, Robin M. Lloyd, M.D., and Julie M. Baughn, M.D. — and their four fellows at the Center for Sleep Medicine work closely with physicians from other subspecialties throughout the pediatric practice, including specialists in pediatric epilepsy, brain tumor, and metabolic and neurodegenerative disorders.

As Dr. Kotagal points out, identification of sleep disorders can affect the management of coexisting conditions, overall health, and cognitive and psychological development. For example, according to Kenneth J. Mack, M.D., Ph.D., a pediatric headache specialist at Mayo Clinic, approximately 75 percent of children with chronic headache have sleep problems. Improved sleep can lessen headache pain or frequency. Sleep disturbance caused by sleep apnea or RLS also can lower the threshold for seizures in children with epilepsy, and sleep treatment can have a positive impact on seizure frequency.

Physical and developmental consequences

Primary sleep disorders can have physical, as well as cognitive and developmental, consequences. Obesity has long been associated with narcolepsy, a disorder caused by loss of hypocretin cells, with a typical age at onset in the teenage years. Dr. Kotagal and his colleagues were among the first to formally link the two disorders, in a retrospective study that found that body mass index was significantly higher in children with narcolepsy than in healthy age- and sex-matched control subjects, regardless of whether drug therapy had been instituted. In an article published in the March 2004 issue of Sleep Medicine, the authors concluded that risk of obesity is inherent in the narcolepsy-cataplexy syndrome and is likely related to hypocretin deficiency.

Secondary sleep disorders are another area of focus at Mayo. Childhood neurodevelopmental disorders, such as Down syndrome, Prader-Willi syndrome, autism and cerebral palsy, also are associated with serious sleep initiation and maintenance problems. "In children with chronic disease, sometimes the only means of improving quality of life is to improve the quality of sleep," Dr. Kotagal says. A child with muscular dystrophy, for example, may have apnea and decreases in oxygen saturation with consequent daytime fatigue due to diminished chest and abdominal wall movement during sleep.

Sleep disturbance also can affect mental health. Collaborating with colleagues in psychiatry, Mayo sleep medicine specialists recently found that two-thirds of children seen at Mayo Clinic with a diagnosis of RLS have an associated depression or anxiety disorder. The rapid growth of the pediatric sleep medicine practice at Mayo is just one example of the increased recognition among health providers that sleep is critical to the developing brain and childhood health and that sleep disturbance can be a factor in a large number of pediatric disorders.

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